Answer:
1) Yes
2) No
3) Yes
4) Yes
Step-by-step explanation:
Remember the rule: the sum of the two shortest sides must be bigger than the longest side. From there, the answers should be obvious. Just add up the smallest sides for each triplet of lengths and see if that is bigger than the largest side.
7 + 14 > 18, therefore this can be a triangle
3 + 8 < 17, therefore this can't be a triangle
3.2 + 9.0 > 11.5, therefore this can be a triangle
6 + 7 > 8, therefore this can be a triangle